Apparatus for cleaning a surface

ABSTRACT

An apparatus for cleaning a surface includes a liquid delivery system for storing cleaning liquid and delivering the cleaning liquid to the surface to be cleaned, a fluid recovery system and a control system. The control system includes a controller that is coupled to a sensing assembly. Methods of operating the same include sensing foam or liquid with the sensing assembly.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/959,397, filed Oct. 4, 2022, which is a continuation of U.S. patentapplication Ser. No. 17/252,596, filed Dec. 15, 2020, which is aNational Phase application of International Application No.PCT/US2019/038383 filed Jun. 21, 2019, which claims the benefit of U.S.Provisional Patent Application No. 62/688,428, filed Jun. 22, 2018, andthe benefit of U.S. Provisional Patent Application No. 62/789,661, filedJan. 8, 2019, all of which are incorporated herein by reference in theirentirety.

BACKGROUND

Several different types of apparatus are known for cleaning a surface.One category of floor cleaning apparatus includes extraction cleanersfor deep cleaning carpets and other fabric surfaces, such as upholstery.Most carpet extractors comprise a liquid delivery system and a liquidrecovery system. The liquid delivery system typically includes one ormore liquid supply tanks for storing a supply of cleaning liquid, aliquid distributor for applying the cleaning liquid to the surface to becleaned, and a liquid supply conduit for delivering the cleaning liquidfrom the liquid supply tank to the liquid distributor. The liquidrecovery system usually comprises a recovery tank, a nozzle adjacent thesurface to be cleaned and in fluid communication with the recovery tankthrough a working air conduit, and a source of suction in fluidcommunication with the working air conduit to draw the cleaning liquidfrom the surface to be cleaned and through the nozzle and the workingair conduit to the recovery tank.

Extraction cleaners for typical household use can be configured as anupright unit having a base for movement across a surface to be cleanedand an upright body pivotally mounted to a rearward portion of the basefor directing the base across the surface to be cleaned, a canister unithaving a cleaning implement connected to a wheeled base by a suctionhose, or a portable extractor adapted to be hand carried by a user forcleaning relatively small areas.

BRIEF SUMMARY

Aspects of the present disclosure relate to a surface cleaning device,including a base adapted for contacting a surface of a surroundingenvironment to be cleaned, a suction source, a suction nozzle in fluidcommunication with the suction source, a fluid supply tank adapted tohold a supply of fluid, a fluid dispenser in fluid communication withthe fluid supply tank, and a recovery container in fluid communicationwith the suction nozzle, a standpipe in the recovery container, thestandpipe forming a flow path between an inlet to the recovery containerand an outlet at an upper end of the standpipe, and a fluid levelsensing assembly including at least one probe and a controllercommunicatively coupled to the at least one probe and configured todetect a level of fluid in the recovery container to define a presenceof liquid.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a schematic view of an apparatus for cleaning a surfaceillustrated as an extraction cleaner according to an aspect of thepresent disclosure.

FIG. 2 is a perspective view of a surface cleaning apparatus accordingto one aspect of the present disclosure.

FIG. 3 is an exploded perspective view of the recovery tank assembly ofthe surface cleaning apparatus of FIG. 2 .

FIG. 4 is an enlarged view of the lid from FIG. 3 .

FIG. 5 is a schematic view of the control system for the cleaningapparatus of FIG. 1 and FIG. 2 .

FIG. 6 is a schematic view of a sensing system from FIG. 1 .

FIG. 7 illustrates a flow chart showing a method for sensing fluid suchas utilizing the sensing system of FIG. 6 according to one aspect of thepresent disclosure.

FIG. 8 illustrates a flow chart showing a method for sensing liquid suchas utilizing the sensing system of FIG. 6 according to another aspect ofthe present disclosure.

FIG. 9 illustrates a flow chart showing a method for sensing foam suchas utilizing the sensing system of FIG. 6 according to yet anotheraspect of the present disclosure.

FIG. 10 is a perspective view of a surface cleaning apparatus accordingto another aspect of the present disclosure.

FIG. 11 is a perspective view of a surface cleaning apparatus accordingto yet another aspect of the present disclosure.

FIG. 12 is a perspective view of a surface cleaning apparatus accordingto still yet another aspect of the present disclosure.

FIG. 13 is a perspective view of a surface cleaning apparatus accordingto further yet another aspect of the present disclosure.

FIG. 14 is an exploded perspective view of another recovery tankassembly that can be included in the surface cleaning apparatus of FIG.2 .

FIG. 15 is a cross-sectional view though the assembled recovery tankassembly of FIG. 13 .

FIG. 16 is a schematic view of a sensing system utilized with therecovery tank assembly of FIG. 14 .

FIG. 17 is a perspective view of a surface cleaning apparatus accordingto an aspect of the present disclosure having a recovery tank assemblyexploded therefrom.

FIG. 18 is a side perspective view of the recovery tank assembly of FIG.17 .

FIG. 19 is a top perspective view of a base of the extraction cleaner ofFIG. 17

FIG. 20 is a perspective view of a surface cleaning apparatus accordingto an aspect of the present disclosure having a recovery tank assemblyexploded therefrom.

FIG. 21 is a cross-sectional view though the assembled recovery tankassembly of FIG. 20 .

FIG. 22 is a schematic view of a sensing system utilized with therecovery tank assembly of FIG. 21 .

DETAILED DESCRIPTION

The present disclosure relates to an apparatus for cleaning a surface,such as an extraction cleaner that delivers cleaning liquid to a surfaceto be cleaned and extracts spent cleaning liquid and debris (which mayinclude dirt, dust, stains, soil, hair, and other debris) from thesurface. In one aspect the surface cleaning apparatus is a multi-surfacewet vacuum cleaner that can be used to clean hard floor surf aces suchas tile and hardwood and soft floor surf aces such as carpet.

According to an aspect of the disclosure, a fluid delivery system forstoring cleaning fluid and delivering the cleaning fluid to the surfaceto be cleaned can be included in the apparatus. The fluid deliverysystem can include a supply tank removably mounted on a housing of theapparatus. The apparatus can further include a latch for securing thesupply tank to the housing. The latch can include a spring-loaded latchconfigured to release the supply tank upon application a sufficientforce to overcome the biased latching force of the latch. A user canconveniently apply sufficient force to the supply tank itself to pullthe supply tank off the housing. The spent cleaning liquid and debriscan be stored in a recovery container within the apparatus. In certainexamples, the recovery tank can further include a removable tankstrainer configured to strain large debris and hair out of the tankprior to emptying.

In one aspect of the present disclosure, a sensing system operablycoupled to the recovery container can elicit an action upon a detectionof liquid or foam within the recovery container at a predeterminedlevel. The recovery system can include a “floatless” sensing systemhaving an electronic liquid level sensing system configured to detectliquid at one or more levels within the recovery tank and determine whento shut-off or otherwise interrupt the recovery system.

Sensing systems disclosed herein include, by way of non-limitingexamples, include a high frequency fluid and foam sensor including oneexample having three probes: one for transmitting and two receivingprobes including one for fluid and one for foam sensing and anotherexample includes two probes with one transmitting probe and onereceiving probe configured for fluid sensing. Another aspect of asensing system described herein includes conductivity sensing systemfeaturing two probes including in one aspect having pins insert-moldedinto the sidewalls of the recovery container. Yet another aspectincludes a self-capacitive sensing system where the probes areconductive pads mounted on the handle assembly behind the recovery tank.Further still, an accelerometer can be included such that the sensingsystem can estimate the tank fill level or volume of liquid in the tankas the floor cleaning device is operated as the accelerometer providesan orientation of the tank and the capacitance sensing provides a fluidlevel for the given orientation.

FIG. 1 is a schematic view of various functional systems of anextraction cleaning apparatus in the form of an extraction cleaner 10.The extraction cleaner 10 can have similarities to the extractioncleaner described in U.S. Patent Application Publication No.2017/0119225, published May 4, 2017 and U.S. Patent ApplicationPublication No. 2015/0108244, published Apr. 23, 2015, both of which areincorporated herein by reference in their entirety.

The functional systems of the extraction cleaner 10 can be arranged intoany desired configuration, such as an upright extraction device having abase and an upright body for directing the base across the surface to becleaned, a canister device having a cleaning implement connected to awheeled base by a suction hose, a portable extractor adapted to be handcarried by a user for cleaning relatively small areas, or a commercialextractor.

The extraction cleaner 10 can include a liquid delivery system 12 forstoring cleaning liquid and delivering the cleaning liquid to thesurface to be cleaned and a recovery system 14 for removing the spentcleaning liquid and debris from the surface to be cleaned and storingthe spent cleaning liquid and debris.

The recovery system 14 can include a suction nozzle 16, a suction source18 in fluid communication with the suction nozzle 16 for generating aworking air stream, and a recovery container 20 for separating andcollecting liquid and debris from the working airstream for laterdisposal. A separator 21 can be formed in a portion of the recoverycontainer 20 for separating liquid and entrained debris from the workingairflow. The recovery container 20 can include a fluid level sensingassembly 98 that includes at least one probe 114. As illustrated in FIG.1 , the fluid level sensing assembly 98 can further include, a secondprobe 116, and a third probe 118, though any number of probes can beincluded depending upon the implementation. The probes 114, 116, 118 inthe recovery container 20 can communicate with a controller (not shown).The fluid level sensing assembly 98 can determine when variouscomponent(s) or sub-systems of the extraction cleaner should beselectively activated or de-energized to prevent an overfill conditionin the recovery container 20. An overfill condition in the recoverycontainer 20 is undesirable because it can cause fluid or foam to leakor spill from the extraction cleaner, thereby soiling the machine andsurface to be cleaned. In addition, an overfill condition can causeliquid or foam ingress into the suction source 18, which can damageinternal components thereof, such as electrical components and bearings,for example.

The suction source 18, such as a motor/fan assembly, is provided influid communication with the recovery container 20. The suction source18 can be electrically coupled to a power source 22, such as a batteryor by a power cord plugged into a household electrical outlet. A suctionpower switch 24 between the suction source 18 and the power source 22can be selectively closed by the user, thereby activating the suctionsource 18.

The suction nozzle 16 can be provided on a base or cleaning head adaptedto move over the surface to be cleaned. An agitator 26 can be providedadjacent to the suction nozzle 16 for agitating the surface to becleaned so that the debris is more easily ingested into the suctionnozzle 16. Some examples of agitators include, but are not limited to, ahorizontally-rotating brushroll, dual horizontally-rotating brushrolls,one or more vertically-rotating brushrolls, or a stationary brush.

The extraction cleaner 10 can also be provided with above-the-floorcleaning features. A vacuum hose 28 can be selectively fluidly coupledto the suction source 18 for above-the-floor cleaning using an above-thefloor cleaning tool 30 with its own suction inlet. A diverter assembly32 can selectively switch between on-the-floor and above-the floorcleaning by diverting fluid communication between either the suctionnozzle 16 or the vacuum hose 28 with the suction source 18.

The liquid delivery system 12 can include at least one liquid container34 for storing a supply of liquid. The liquid can include one or more ofany suitable cleaning liquids, including, but not limited to, water,compositions, concentrated detergent, diluted detergent, etc., andmixtures thereof. For example, the liquid can include a mixture of waterand concentrated detergent.

The liquid delivery system 12 can further include a flow control system36 for controlling the flow of liquid from the container 34 to a liquiddistributor 38. In one configuration, the flow control system 36 caninclude a pump 40 which pressurizes the liquid delivery system 12 and aflow control valve 42 which controls the delivery of liquid to thedistributor 38. An actuator 44 can be provided to actuate the flowcontrol system 36 and dispense liquid to the distributor 38. Theactuator 44 can be operably coupled to the valve 42 such that pressingthe actuator 44 will open the valve 42. The valve 42 can be electricallyactuated, such as by providing an electrical switch 46 between the valve42 and the power source 22 that is selectively closed when the actuator44 is pressed, thereby powering the valve 42 to move to an openposition. In one example, the valve 42 can be a solenoid valve. The pump40 can also be coupled with the power source 22.

The liquid distributor 38 can include at least one distributor outlet 48for delivering liquid to the surface to be cleaned. The at least onedistributor outlet 48 can be positioned to deliver liquid directly tothe surface to be cleaned, or indirectly by delivering liquid onto theagitator 26. The at least one distributor outlet 48 can include anystructure, such as a nozzle or spray tip; multiple outlets 48 can alsobe provided. As illustrated in FIG. 1 , the distributor 38 can includetwo outlets 48 which distribute cleaning liquid to the surface to becleaned. For above-the-floor cleaning, the cleaning tool 30 can includean auxiliary distributor (not shown) coupled with the liquid deliverysystem 12.

Optionally, a heater 50 can be provided for heating the cleaning liquidprior to delivering the cleaning liquid to the surface to be cleaned. Inthe example illustrated in FIG. 1 , an in-line heater 50 can be locateddownstream of the container 34 and upstream of mixing pump 40. Othertypes of heaters 50 can also be used. In yet another example, thecleaning liquid can be heated using exhaust air from a motor-coolingpathway for the suction source 18.

As another option, the liquid delivery system can be provided with asecond container 52 for storing a cleaning liquid. For example, thefirst container 34 can store water and the second container 52 can storea cleaning agent such as detergent. The containers 34, 52 can, forexample, be defined by a supply tank and/or a collapsible bladder. Inone configuration, the first container 34 can be a bladder that isprovided within the recovery container 20. Alternatively, a singlecontainer can define multiple chambers for different liquids.

In the case where multiple containers 34, 52 are provided, the flowcontrol system 36 can further be provided with a mixing system 54 forcontrolling the composition of the cleaning liquid that is delivered tothe surface. The composition of the cleaning liquid can be determined bythe ratio of cleaning liquids mixed together by the mixing system. Asshown herein, the mixing system 54 includes a mixing manifold 56 thatselectively receives liquid from one or both of the containers 34, 52. Amixing valve 58 is fluidly coupled with an outlet of the secondcontainer 52, whereby when mixing valve 58 is open, the second cleaningliquid will flow to the mixing manifold 56. By controlling the orificeof the mixing valve 58 or the time that the mixing valve 58 is open, thecomposition of the cleaning liquid that is delivered to the surface canbe selected.

In yet another configuration of the liquid delivery system 12, the pump40 can be eliminated and the distributor 38 can include a gravity-feedsystem having a valve fluidly coupled with an outlet of the container(s)34, 52, whereby when valve is open, liquid will flow under the force ofgravity to the distributor 38. The valve can be mechanically actuated orelectrically actuated, as described above.

The extraction cleaner 10 shown in FIG. 1 can be used to effectivelyremove debris and liquid from the surface to be cleaned in accordancewith the following method. The sequence of steps discussed is forillustrative purposes only and is not meant to limit the method in anyway as it is understood that the steps may proceed in a differentlogical order, additional or intervening steps may be included, ordescribed steps may be divided into multiple steps, without detractingfrom aspects of the present disclosure.

FIG. 2 is a perspective view illustrating one non-limiting example of asurface cleaning apparatus in the form of multi-surface wet vacuumextraction cleaner 10, according to one aspect of the presentdisclosure. As illustrated herein, the extraction cleaner 10 is anupright multi-surface wet vacuum cleaner having a housing that includesan upright body or handle assembly 60 and a base 62 pivotally and/orswivel mounted to the upright handle assembly 60 and adapted formovement across a surface to be cleaned. For purposes of descriptionrelated to the figures, the terms “upper,” “lower,” “right,” “left,”“rear,” “front,” “vertical,” “horizontal,” “inner,” “outer,” andderivatives thereof shall relate as oriented in FIG. 2 from theperspective of a user behind the extraction cleaner 10, which definesthe rear of the extraction cleaner 10. However, it is to be understoodthat aspects of the present disclosure may assume various alternativeorientations, except where expressly specified to the contrary.

The upright handle assembly 60 includes an upper handle 64 and a frame66. Upper handle 64 includes a handle assembly 68. Frame 66 includes amain support section or body assembly 70 supporting at least a cleantank assembly 72 and a recovery tank assembly 74, and may furthersupport additional components of the handle assembly 60. The base 62includes a foot assembly 76. The extraction cleaner 10 can include afluid delivery or supply pathway, including and at least partiallydefined by the clean tank assembly 72, for storing cleaning fluid anddelivering the cleaning fluid to the surface to be cleaned and a fluidrecovery pathway, including and at least partially defined by therecovery tank assembly 74, for removing the spent cleaning fluid anddebris from the surface to be cleaned and storing the spent cleaningfluid and debris until emptied by the user.

A pivotable swivel joint assembly 78 is formed at a lower end of theframe 66 and moveably mounts the base 62 to the handle assembly 60. Inthe illustrated aspect of the present disclosure, the base 62 can pivotup and down about at least one axis relative to the handle assembly 60.The pivotable swivel joint assembly 78 can alternatively include auniversal joint, such that the base 62 can pivot about at least two axesrelative to the handle assembly 60. Wiring and/or conduits supplying airand/or liquid between the base 62 and the handle assembly 60, or viceversa, can extend though the pivotable swivel joint assembly 78. Aswivel locking mechanism (not shown) can be provided to lock and/orrelease the swivel joint assembly 78 for movement.

FIG. 3 is an exploded perspective view of the recovery tank assembly 74.The recovery tank assembly 74 generally includes the collectioncontainer for the fluid recovery system. In the present example, therecovery tank assembly 74 includes the recovery container 20 with anintegral hollow standpipe formed therein. A lid 82 sized for receipt onthe recovery container 20 supports a pleated filter 84 in a filter coverplate 86 mounted to the lid 82 with a mesh screen 88 therebetween. Thedetails of the pleated filter 84 and mesh screen 88 are not shownherein. Preferably, the pleated filter 84 is made of a material thatremains porous when wet. The extraction cleaner 10 can also be providedwith one or more additional filters upstream or downstream. A gasket 90positioned between mating surfaces of the lid 82 and the recoverycontainer 20 creates a seal therebetween for prevention of leaks.

A releasable latch 100 is provided to facilitate removal of the recoverytank assembly 74 for emptying or cleaning. The releasable latch 100 canbe positioned in an aperture 102 on a front side of the lid 82. Thereleasable latch 100 can include a latch button 104 held within a latchbracket 106 and biased with latch spring 108 toward an engaged orlatched position. The latch button 104 releasably engages with a frontcover (not shown) to removably secure the recovery tank assembly 74 tothe body assembly 70 (FIG. 2 ). A hand grip 110 can be provided on therecovery container 20 and located below the latch 100 to facilitatehandling of the recovery tank assembly 74.

A shut-off valve (not shown) can be provided for interrupting suctionwhen liquid or foam in the recovery container 20 reaches a predeterminedlevel. The shut-off valve can be positioned in any suitable manner andinclude any suitable type of valve. The fluid level sensing assembly 98can be configured to determine when such shut-off valve should beactivated. The fluid level sensing assembly 98 can include any suitableassembly for sensing one of at least liquid or foam at one or morelevels within the recovery container 20 or other portions of theextraction cleaner 10. In the illustrated example, at least one sidebracket assembly 92 a, 92 b is fixedly attached to the lid 82 in aposition offset from the standpipe (not shown). Further still, at leastone front bracket assembly 92 c is attached to the lid 82 adjacent anair outlet 96.

FIG. 4 is an enlarged perspective view of the lid 82 that includes anon-limiting example of the fluid level sensing assembly 98. The fluidlevel sensing assembly 98 includes at least one bracket assembly 92 a,92 b, 92 c, and at least one probe 114, 116, 118. Each probe 114, 116,118 includes at least one conductor 112 a, 112 b, 112 c operably coupledto a communication channel 120. In the illustrated example, the firstprobe 114 includes a communication channel 120 that operably couples toa first conductor 112 a of a first side bracket assembly 92 a.Similarly, the second probe 116 includes a communication channel 120that operably couples to a second conductor 112 b of a second sidebracket assembly 92 b. The first and second probes 114, 116 can bemounted at relatively the same location on the first and second sidebrackets 92 a, 92 b. The structure of the first and second side brackets92 a, 92 b can be similar in dimension and can result in the first andsecond probes 114, 116 being at a similar depth when the lid 82 iscoupled to the recovery container 20. The third probe 118 can beoperably coupled to a third conductor 112 c of a front bracket assembly92 c. Optionally, the third conductor 112 c can communicate with thethird probe 118 via a communication channel 120.

The conductors 112 a, 112 b, 112 c can be formed of any object ormaterial that transmits electricity including, but not limited to: metalplates; insert molded, formed metal plates with selectively exposedsections; metal pins with selectively masked upper sections; etc.Selectively masked or selectively exposed materials can be configuredsuch that the masked or exposed areas are selected to enhance thesensing performance of the probe 114, 116, 118.

One or more communication channels 120 can couple to the first probe114, second probe 116, and third probe 118, respectively. Thecommunication channels 120 can be formed of any physical transmissionmedia useful for transmitting signals or conveying data including, butis not limited to, copper wire, twisted pair wire, fiber optic cable,printed circuit board trace, solder, or, in the case of wirelesssignals, air.

It has been considered that any number of additional bracket assembliescan be coupled to a variety of locations on the lid 82. The location ofat least one probe with at least one conductor can be located in anyposition relative to the bracket assembly. When the lid 82 is coupled tothe recovery container 20, the side bracket assemblies 92 a, 92 b andfront bracket assembly 92 c can be contained within the recoverycontainer 20. It is further contemplated that the probes 114, 116, 118can be molded directly into the side walls of the recovery tank 20,thereby eliminating the bracket assemblies.

FIG. 5 is a schematic view of the control system 124 for the extractioncleaner 10. The controller 122 can couple to the first probe 114, secondprobe 116, and third probe 118 of the fluid level sensing assembly 98using one or more communication channels 120. The controller 122 canalso be operationally connected to other aspects of the extractioncleaner 10. A non-limiting example of objects operationally connectedwith the controller 122 include the suction source 18, a pump 40, anagitator 26, a user interface 132, or additional sensors 134. Additionalsensors 134 can include, but are not limited to, additional recoverytank sensors, temperature sensors, shut off valves, or electricalswitches.

In operation, the extraction cleaner 10 is prepared for use by couplingthe extraction cleaner 10 to the power source 22, and by filling thefirst container 34, and optionally the second container 52, withcleaning liquid. Cleaning liquid is selectively delivered to the surfaceto be cleaned via the liquid delivery system 12 by user-activation ofthe actuator 44, while the extraction cleaner 10 is moved back and forthover the surface. The agitator 26 can simultaneously agitate thecleaning liquid into the surface to be cleaned. During operation of therecovery system 14, the extraction cleaner 10 draws in liquid anddebris-laden working air through the suction nozzle 16 or cleaning tool30, depending on the position of the diverter assembly 32, and into thedownstream recovery container 20 where the liquid debris issubstantially separated from the working air. The air flow then passesthrough the suction source 18 prior to being exhausted from theextraction cleaner 10. The recovery container 20 can be periodicallyemptied of collected liquid and debris.

During operation, the recovery container 20 is typically coupled to thelid 82. As illustrated in FIG. 6 , the first probe 114 of the fluidlevel sensing assembly 98 can emit a liquid sensing signal 136 from thecontroller 122 at a first frequency 138. The liquid sensing signal 136travels from the first probe 114 through contents of the recoverycontainer 20 to form a liquid response signal 140 that is detected bythe second probe 116. The second probe 116 can be located in therecovery container 20 at a critical liquid level. The term criticalliquid level is used herein to define a level or location where, ifliquid is present, the cleaning/suction components (e.g. the suctionsource 18 and the liquid delivery system 12) of the extraction cleaner10 should be shut down to prevent liquid ingress into the suction source18. The liquid response signal 140 received by the second probe 116 iscommunicated with the controller 122. Based on the liquid responsesignal 140, the controller 122 can turn off components of the extractioncleaner 10. Additionally or alternatively, the controller 122, based onthe liquid response signal 140, can provide a visual or audible signalsuch as a light or sound via the user interface 132. The light or soundcan provide an alert to the user that the liquid is too high in therecovery container 20 or that portions of the extraction cleaner 10 havebeen turned off. In yet another configuration, the controller 122 canadditionally or alternatively activate a shut-off valve in response tothe liquid response signal 140 to prevent liquid ingress into thesuction source 18.

The first probe 114 can also emit a foam sensing signal 142 from thecontroller 122 at a second frequency 144. The foam sensing signal 142travels from the first probe 114 through contents of the recoverycontainer 20 to form a foam response signal 146 that is detected by thethird probe 118. The third probe 118 can be located in the recoverycontainer 20 at a critical foam level; that is, the location where, iffoam is present, the cleaning/suction components of the extractioncleaner 10 should be shut down to prevent foam ingress into the suctionsource 18. The foam response signal 146 received by the third probe 118is communicated with the controller 122. Based on the foam responsesignal, the controller 122 can turn off components of the extractioncleaner 10. Non-limiting examples of components that can be turned offinclude the suction source 18 and the liquid delivery system 12.Additionally or alternatively, the controller 122, based on the foamresponse signal 146, can provide a visual or audible signal such as alight or sound via the user interface 132. The light or sound canprovide an alert to the user that the foam is too high in the recoverycontainer 20. In yet another configuration, the controller 122 canadditionally or alternatively activate a shut-off valve in response tothe foam response signal 140 to prevent foam ingress into the suctionsource 18.

It will be understood that the basic function of the control system 124is to determine if either of two tank full conditions are met. The firstcondition is when dense, liquid water has risen to contact both thefirst probe 114 and the second probe 116. The second condition is whenliquid foam or thin water rivulets have filled the area between thefirst probe 114 and the third probe 118. Action can also be taken by thecontrol system to shut down at least one of the suction source 18, suchas the motor/fan assembly, the pump 40, or the agitator 26. Taking atleast one of these actions and more beneficially all of these actionsprevents additional water from being suctioned into the recoverycontainer 20.

In one working example, the primary operation passes a 380 kHz squarewave into an electrode forming the first probe 114 suspended in therecovery container 20. When liquid water bridges this electrode with thesecond probe 116, an electrode also suspended in the recovery container20, the signal is received by second probe 116 with a limited slew rate.The output signal can be directed through one or more signals filtersincluding, but not limited to analog circuitry configured to conditionthe signal, and the output from second probe 116 is capacitively coupledto a buffer-amp input to provide a 380 kHz analog signal output centeredaround zero and protecting the signal from downstream filtering. Thebuffer-amp provides adequate impedance from downstream circuitry andoutputs an analog half-wave signal. The foam sensor is electronicallysimilar to the liquid sensor, but a lower frequency signal (79 kHz) istransmitted effectively by foam to the third probe 118. The secondop-amp channel of the buffer-amp such as provided on exemplary amplifierLM 6142, is used for the foam sensing portion of the circuit. When soapfoam of sufficient density bridges between the first probe 114 and thethird probe 118, the controller 112 can interpret this signal to shutdown operation before excessive foam is ingested by the suction source18.

FIG. 7 illustrates a method 200 for sensing liquid or foam using thefluid level sensing assembly 98 according to one aspect of the presentdisclose. At 202, the liquid sensing signal 136 is generated and emittedfrom the first probe 114. Additionally or alternatively at 202, the foamsensing signal 142 is generated and emitted from the first probe 114. At204, the liquid sensing signal 136, or the foam sensing signal, or boththe liquid sensing signal 136 and the foam sensing signal 142 transmitthrough the recovery container 20. At 206, after transmitting throughthe recovery container 20, the liquid and foam sensing signals 136, 142are detected as the liquid or foam response signal 140, 146 and by thesecond probe 116 and the third probe 118, respectively. The second probe116 communicates the detected liquid response signal 140 to thecontroller 122. Additionally or alternatively the third probe 118communicates the detected foam response signal 146 to the controller122. The controller 122 receives the liquid response signal 140 anddetermines if liquid has been sensed between the first probe 114 and thesecond probe 116. Additionally or alternatively at 212 the controller122 receives the foam response signal 146 and determines if foam hasbeen sensed between the first probe 114 and the third probe 118.

To accomplish the step 206 of determining the state of the sensedsignals, the fluid level sensing assembly 98 can include additionalcomponents to condition the received signals. In one non-limitingexample, the fluid level sensing assembly 98 can include electroniccomponents to capacitively couple and smooth the signal such that therise time of the response or the average amplitude of the voltage of thereceived signal can be determined. In another non-limiting example, thecontroller 122 can be configured to perform one or more signalprocessing algorithms on the received signal to determine one or morecharacteristics of the received signal. Signal processing algorithmsincorporated into the controller 122 for assisting in the determinationof one or more characteristics of the received signal can include, butare not limited to, blind source separation, principal componentanalysis, singular value decomposition, wavelet analysis, independentcomponent analysis, cluster analysis, Bayesian classification, etc.

At 208, if liquid or foam have not been detected at 206 an action isinitiated to repeat the method 200 including to generate the signals at202. At 208, if liquid or foam have been detected at 206, an action isinitiated to alert the user. The action that alerts the user can be, butis not limited to, turning off components of the extraction cleaner 10.Additionally or alternatively, a visual or audible signal such as alight or sound can alert a user via the user interface 132.

It is contemplated that any of the probes of the fluid level sensingassembly 98 can be configured to transmit, receive or transmit andreceive one or more sensing signals. The sensing signals can include anywaveform useful in sensing water or foam levels, including, but notlimited to, square waves, sine waves, triangle waves, sawtooth waves,and combinations thereof. Furthermore, the sensing signals can includeany frequency useful in sensing water or foam levels, including, but notlimited to, frequencies ranging from approximately 10 kilohertz to 10megahertz. In one non-limiting example, the foam sensing and liquidsensing signals can be multiplexed and transmitted simultaneously to oneor more probes.

FIG. 8 illustrates a method 200 a for sensing liquid according toanother aspect of the present disclose. The method 200 a is similar tothe method 200, however, the method 200 a is specific to the detectionof liquid. At 202 a, generating signals can be, for example, at 302, asquare wave generated by a controller 122 with a first frequency (f₁). Anon-limiting example value for the first frequency (f₁) can be 380kilohertz. A non-limiting example value for the range of the inputsquare wave is from 0 volts to 5 volts. Optionally, at 304, a delay forduration for a first time length (t₁) can occur before a measurement istaken. A non-limiting example value for the first time (t₁) can be 30milliseconds.

At 204 a, an example of transmitting signals can include, at 306, afirst set of voltages (V_(RX11)) are measured with a first cardinality(N₁). A non-limiting example value for the first cardinality (N₁) is 15samples. When the first cardinality (N₁) is 15 samples; the first set ofvoltages (V_(RX11)) include 15 voltage measurements taken at the secondprobe 116.

At 206 a, an example of determining can begin with the controller 122 at308 determines how many sample voltages (n TL) from the first set ofvoltages (V_(RX11)) exceed a first threshold (T_(V1)). A non-limitingexample value for the first threshold (T_(V1)) is 683 millivolts. Thenumber of sample voltages (n_(TL)) that exceed the first threshold(T_(V1)) is than compared to a second threshold (T_(V2)) at 310. If thenumber of sample voltages (n TL) in the first set of voltages (V_(RX11))that exceed the first threshold (T_(V1)) is less than the secondthreshold (T_(V2)), an action is initiated at 208 a that can include, at322 ending the method 200 a for sensing liquid and beginning a method200 b for sensing foam.

Alternatively, in 206 a at 310, if the number of sample voltages(n_(TL)) in the first set of voltages (V_(RX11)) that exceed the firstthreshold (T_(V1)) is more than the second threshold (T_(V2)), then thecardinality is increased at 312 so that a second set of voltages(V_(RX12)) has a second cardinality (N₂). A non-limiting example valuefor the second cardinality (N₂) is 45 samples. The second set ofvoltages (V_(RX12)) with the second cardinality (N₂) are measured at 314and combined in union with the first set of voltage measurements(V_(RX11)) to form a merged voltage set (V_(RX1)) In 316, the controller122 determines the number of elements (n TH) in the merged voltage set(V_(RX1)) that exceed a third threshold (T_(V2)). A non-limiting examplevalue for the third threshold (T_(V2)) can be 292 millivolts. At 318,the number of elements (n_(TH)) in the merged voltage set (V_(RX1)) thatexceed the third threshold (T_(V2)) is compared to a fourth threshold(T₄). A non-limiting example value for the fourth threshold is 20. Ifthe number of sample voltages (n TH) in the merged set of voltages(V_(RX1)) that exceed the third threshold (T_(V2)) is less than thefourth threshold (T₄), an action is initiated at 322 of 208 a that endsthe method 200 a for sensing liquid and begins a method 200 b forsensing foam.

Alternatively, at 318 of 206 a, if the number of sample voltages (n TH)in the merged set of voltages (V_(RX1)) that exceed the third threshold(T_(V2)) is more than the fourth threshold (T₄), then an action isinitiated at 320 of 208 a that generates a first alert. Additionally,once the first alert is activated, the method 200 a for sensing liquidends and a method 200 b for sensing foam can begin at 322. Additionally,or alternatively, once the first alert is activated at 320, the method200 a for sensing liquid ends and the controller 122 can disableelements of the extraction cleaner Therefore, it will be understood thatthe method need not continue on to sense foam.

The first alert, triggered by a specific drop in voltage, indicates thatliquid is present between the first probe 114 and the second probe 116,where the second probe 116 is positioned in the recovery container 20 atthe critical liquid level at which point additional liquid added to therecovery container 20 could damage the extraction cleaner 10.

FIG. 9 illustrates a method 200 b for sensing foam according to anotheraspect of the present disclosure. The method 200 b is similar to themethod 200, however, the method 200 b is specific to the detection offoam. At 202 b generating signal(s) can occur when, for example, at 402,the controller 122 generates a square wave with a second frequency (f₂).A non-limiting example value for the second frequency (f₂) can be 79kilohertz. A non-limiting example value for the range of the inputsquare wave is from 0 volts to 5 volts. Optionally, at 404, a delay forduration for a second time length (t₂) can occur before a measurement istaken. A non-limiting example value for the second time (t₂) can be 30milliseconds. At 204 b, a transmission of signal can occur, for example,at 406, when a first set of foam voltages (V_(RX21)) are measured with afirst foam cardinality (N_(IF)). A non-limiting example value for thefirst foam cardinality (N_(IF)) is samples. When the first foamcardinality (N_(IF)) is 15 samples; the first set of foam voltages(V_(RX21)) include 15 voltage measurements taken at the third probe 118.At 206 b, determination can begin, for example, at 408 when thecontroller 122 determines how many sample foam voltages (n_(TLF)) fromthe first set of foam voltages (V_(RX21)) exceed a fifth threshold(T_(V1F)). A non-limiting example value for the fifth threshold(T_(V1F)) is 977 millivolts. At 410, the number of sample foam voltages(n_(TLF)) that exceed the fifth threshold (T_(V1F)) is then compared toa sixth threshold (T_(V2F)). At 410, if the number of sample foamvoltages (n_(TLF)) in the first set of foam voltages (V_(RX21)) thatexceed the fifth threshold (T_(V1F)) is less than the sixth threshold(T_(V2F)), an action is initiated at 208 b that can be, for example, at426, an end to the method 200 b for sensing foam and a return to themethod 200 a for sensing liquid.

Alternatively, at 410 of 206 b, if the number of sample foam voltages(n_(TLF)) in the first set of foam voltages (V_(RX21)) that exceed thefifth threshold (T_(V1F)) is more than the sixth threshold (T_(V2F)),then the cardinality is increased at 412 so that a second set of foamvoltages (V_(RX22)) has a second foam cardinality (N_(2F)). Anon-limiting example value for the second foam cardinality (N_(2F)) is45 samples. The second set of foam voltages (V_(RX22)) with the secondfoam cardinality (N_(2F)) are measured in 414 and combined in union withthe first set of foam voltage measurements (V_(RX21)) to form a mergedfoam voltage set (V_(RX2)) In 416, the controller 122 determines thenumber of foam elements (n_(THF)) in the merged foam voltage set(V_(RX2)) that exceed a seventh threshold (T_(V2F)). A non-limitingexample value for the seventh threshold (T_(V2F)) can be 977 millivolts.At 418, the number of foam elements (n_(THF)) in the merged foam voltageset (V_(RX2)) that exceed the seventh threshold (T_(V2F)) is compared toan eighth threshold (T₈). A non-limiting example value for the eightthreshold (T₈) can be 20. If the number of sample foam voltages(n_(THF)) in the merged foam voltage set (V_(RX2)) that exceed theseventh threshold (T_(V2F)) is less than the eighth threshold (T₈) at418, an action is initiated at 208 b that can be to end the method 200 bfor sensing foam and restart the method 200 a for sensing liquid at 426.

Alternatively, at 418 of 206 b, if the number of sample foam voltages(n_(THF)) in the merged foam voltage set (V_(RX2)) that exceed theseventh threshold (T_(V2F)) is more than the eighth threshold (T₈), thenthe controller 122 determines a number of consecutive cycles (n_(FC)) at420. To calculate number of consecutive cycles (n_(FC)), the controller122 can first review the merged foam voltage set (V_(RX2)) to find whena foam voltage from the merged foam voltage set (V_(RX2)) is less thanthe seventh threshold. Once a foam voltage element meets thisqualification, the controller 122 can look at the next foam voltageelement in the merged foam voltage set (V_(RX2)) and can count how manyconsecutive times the foam voltage element is less than the sevenththreshold (T_(V2F)). At 422, the number of consecutive cycles (n_(FC))in the merged foam voltage set (V_(RX2)) is compared to a ninththreshold (T₉). A non-limiting example value for the ninth threshold(T₉) can be 2. If the number of consecutive cycles (n_(FC)) in themerged foam voltage set (V_(RX2)) is less than the ninth threshold (T₉)at 422, an action is initiated at 426 of 208 b that ends the method 200b for sensing foam and restarts the method 200 a for sensing liquid.

Alternatively, in 206 b if the number of consecutive cycles (n_(FC)) inthe merged foam voltage set (V_(RX2)) is more than the ninth threshold(T₉), an action is initiated that generates a second alert at 424 of 208b.

Optionally, once the second alert is activated at 424, then at 426 themethod 200 b for sensing foam ends and the method 200 a for sensingliquid can begin.

Additionally, or alternatively, once the second alert is activated at424, the method 200 b for sensing foam ends and the controller 122 candisable elements of the extraction cleaner 10. Therefore, it will beunderstood that the method need not continue on to sense liquid.

The second alert at 424, triggered by a specific drop in voltage,indicates that foam is present between the first probe 114 and the thirdprobe 118, where the third probe 118 is positioned in the recoverycontainer 20 at the critical foam level at which point additional foamadded to the recovery container 20 could damage the extraction cleaner10.

FIG. 10 is a perspective view illustrating one non-limiting example ofan extraction cleaner 510 that is also known as a spot cleaningapparatus. The extraction cleaner or spot cleaning apparatus 510 can beused for unattended or manual cleaning of spots and stains on carpetedsurfaces and can be structurally and operably similar to U.S. Pat. No.7,228,589 issued Jun. 12, 2007, which is incorporated herein byreference in its entirety. The extraction cleaner can include varioussystems and components schematically described for FIG. 1 , includingthe liquid delivery system 12 for storing and delivering a cleaningfluid to the surface to be cleaned and the recovery system 14 forextracting and storing the dispensed cleaning fluid, dirt and debrisfrom the surface to be cleaned. The extraction cleaner or spot cleaningapparatus 510 includes a bottom housing or portion 502, a top housing orportion 504, a clean tank assembly 506, a recovery tank assembly 508, acarriage assembly, a motor/fan assembly, and a pump assembly. The bottomhousing 502 rests on a surface to be cleaned, and the top housing 504and the bottom housing 502 mate to form a cavity therebetween. A handle516 is integrally formed at an upper surface of the top housing 504 tofacilitate easy carrying of the extraction cleaner or spot cleaningapparatus 510. Optionally, below the handle 516, are various switches539, 541, and 543 to control operation of the extraction cleaner 510.Additionally, one or more indicator lights 545 can be located adjacentto the switches 539, 541, and 543.

A carriage assembly lens 518 is attached to a forward lower section ofthe bottom housing 502 to define an opening in the underside of thebottom housing 502 and is preferably made from a transparent materialfor visibility of the carriage assembly located behind the carriageassembly lens 518. Hose recesses 520 are integrally formed in a lowersurface of the top housing 504 in forward and rearward locations thatcan hold a flexible hose 538. The recovery tank assembly 508 canincludes a fluid level sensing assembly 598, the details of which arenot shown herein, coupled to a controller (not shown). Similarly to thefluid level sensing assembly 98 from FIG. 4 , the fluid level sensingassembly 598 can include at least one probe with at least one conductorwherein the fluid level sensing assembly 598 can detect a liquid or afoam level in the recovery tank assembly 508. The fluid level sensingassembly 598 can complete one or more methods 200, 200 a, 200 b, bytaking measurements to determine critical fluid level, liquid level, orfoam level and acting on the determination.

FIG. 11 is a perspective view illustrating one non-limiting example ofan extraction cleaner 610, according to yet another aspect of thepresent disclosure. As illustrated herein, the extraction cleaner 610 isan upright extraction cleaner having a housing that includes an uprightassembly 660 that is pivotally connected to a base assembly 662 fordirecting the base assembly 662 across the surface to be cleaned. Theextraction cleaner 610 can include the various systems and componentsschematically described for FIG. 1 , including the liquid deliverysystem 12 for storing and delivering a cleaning fluid to the surface tobe cleaned and the recovery system 14 for extracting and storing thedispensed cleaning fluid, dirt and debris from the surface to becleaned. The various systems and components schematically described forFIG. 1 , including the liquid delivery system 12 and fluid recoverysystem 14 can be supported by either or both the base assembly 662 andthe upright assembly 660.

The upright assembly 660 includes a main support section or frame 664supporting components of the liquid delivery system 12 and the recoverysystem 14, including, but not limited to, the recovery container 620 andthe fluid supply container 634. The recovery container 620 and the fluidsupply container 634 function in the same way as the recovery container20 and the first container 34 from FIG. 1 . Additional details of asuitable recovery container for the extraction cleaner 610, which caninclude an air/liquid separator assembly (not shown) are disclosed inU.S. Patent Application Publication No. 2017/0071434, published Mar. 16,2017, which is incorporated herein by reference in its entirety. Theupright assembly 660 also has an elongated handle 666 extending upwardlyfrom the frame 664 that is provided with a hand grip 668 at one end thatcan be used for maneuvering the extraction cleaner 610 over a surface tobe cleaned. The frame 664 of the upright assembly 660 can includecontainer receivers for respectively receiving the recovery and supplycontainers 620, 634 for support on the upright assembly 660. A motorhousing is formed at a lower end of the frame 664 and contains themotor/fan assembly positioned therein in fluid communication with therecovery container 620. Additional details of suitable containerreceivers and motor housing are disclosed in U.S. Patent ApplicationPublication No. 2017/0071434, incorporated above.

The extraction cleaner 610 can also include a base housing 674 that caninclude, but is not limited to, wheels 676, a suction nozzle 616, andone or more agitators 684.

The recovery container 620 of the extraction cleaner 610 can include afluid level sensing assembly 698, the details of which are not shownherein, connected to a controller (not shown). Similarly to the fluidlevel sensing assembly 98 from FIG. 4 , the fluid level sensing assembly698 can include at least one probe with at least one conductor whereinthe fluid level sensing assembly 698 can detect a liquid or a foam levelin the recovery container 620. The fluid level sensing assembly 698 cancomplete one or more methods 200, 200 a, 200 b, by taking measurementsto determine critical fluid level, liquid level, or foam level andacting on the determination.

FIG. 12 is a perspective view illustrating one non-limiting example ofan extraction cleaner 710, according to still yet another aspect of thepresent disclosure. FIG. 12 is a perspective view of a handheldextraction cleaner 710. As illustrated herein, the extraction cleaner710 is adapted to be handheld and portable, and can be easily carried orconveyed by hand. The hand-carriable extraction cleaner 710 can have aunitary body 712 provided with a carry handle 714 attached to theunitary body 712, and is small enough to be transported by one user(i.e. one person) to the area to be cleaned. The carry handle 714 caninclude a power switch 704 or a charging port 706.

The handheld extraction cleaner 710 includes a unitary body 712 orhousing that carries the various functional systems of the extractioncleaner 710. The extraction cleaner 710 can include the various systemsand components schematically described for FIG. 1 , including the liquiddelivery system 12 for storing and delivering a cleaning fluid to thesurface to be cleaned and the recovery system 14 for extracting andstoring the dispensed cleaning fluid, dirt and debris from the surfaceto be cleaned. The various systems and components schematicallydescribed for FIG. 1 , including the liquid delivery system 12 and fluidrecovery system 14 can be supported by either or both a supply tank 726to deliver cleaning fluid to a surface to be cleaned through a fluidoutlet 730 or a working fluid path through the unitary body 712.

The recovery system includes the working fluid path through the unitarybody 712. The working fluid path can be formed by, among other elements,a suction nozzle 738 defining the fluid inlet 716, a suction source influid communication with the suction nozzle 738 for generating a workingair stream, a recovery container 720 for separating and collecting fluidand debris for later disposal, and exhaust vents 722. The suction nozzle738 can also include a cover 736. An agitator 740 can be adjacent to orcouple to the suction nozzle 738.

The recovery system can further include a separator for separating fluidand entrained debris from the fluid path. The separated fluid and debriscan be collected in the recovery container 720. One example of asuitable separator is disclosed in U.S. Pat. No. 7,225,503, issued Jun.5, 2007, which is incorporated herein by reference in its entirety.Other examples of suitable separators are disclosed in U.S. Pat. No.6,189,178, issued Feb. 20, 2001, and U.S. Pat. No. 6,968,593, issuedNov. 29, 2005, both of which are incorporated herein by reference intheir entirety.

Further the extraction cleaner 710 can be structurally and operablysimilar to the extraction cleaner of U.S. Patent Application PublicationNo. 2018/0116476, published May 3, 2018, which is incorporated herein byreference in its entirety.

The recovery container 720 of the extraction cleaner 710 can include afluid level sensing assembly 798, the details of which are not shownherein, connected to a controller (not shown). Similarly to the fluidlevel sensing assembly 98 from FIG. 4 , the fluid level sensing assembly798 can include at least one probe with at least one conductor whereinthe fluid level sensing assembly 798 can detect a liquid or a foam levelin the recovery container 720. The fluid level sensing assembly 798 cancomplete one or more methods 200, 200 a, 200 b, by taking measurementsto determine critical fluid level, liquid level, or foam level andacting on the determination.

FIG. 13 is a perspective view illustrating one non-limiting example ofan extraction cleaner or autonomous vacuum cleaner 810, according tofurther yet another aspect of the present disclosure. The autonomousvacuum cleaner 810 has been illustrated as a robotic vacuum cleaner thatmounts the components various functional systems of the vacuum cleanerin an autonomously moveable unit or housing 812, including components ofa vacuum collection system for generating a working air flow forremoving dirt (including dust, hair, and other debris) from the surfaceto be cleaned and storing the dirt in a collection space on the vacuumcleaner, and a drive system for autonomously moving the vacuum cleanerover the surface to be cleaned. The autonomous vacuum cleaner 810 can bestructurally and operably similar to the autonomous vacuum cleaner ofU.S. Application Publication No. 2018/0078106 published Mar. 22, 2018which is incorporated herein by reference in entirety. The autonomousvacuum cleaner 810 can include a brush chamber 836 at a front of theautonomous unit 812 in which an agitator can be mounted.

The autonomous vacuum cleaner 810 includes a vacuum collection systemcan include a working air path through the unit having an air inlet andan air outlet, a suction nozzle, a suction source in fluid communicationwith the suction nozzle for generating a working air stream, and a dirtbin 818 for collecting dirt from the working airstream for laterdisposal. The suction nozzle can define the air inlet of the working airpath. The suction source can be a motor/fan assembly carried by the unit812, fluidly upstream of the air outlet, and can define a portion of theworking air path. The dirt bin 818 can also define a portion of theworking air path, and include a dirt bin inlet in fluid communicationwith the air inlet. A separator can be formed in a portion of the dirtbin 818 for separating fluid and entrained dirt from the workingairstream. Some non-limiting examples of the separator include a cycloneseparator, a filter screen, a foam filter, a HEPA filter, a filter bag,or combinations thereof.

It is contemplated that the autonomous vacuum cleaner 810 can beconfigured to be an autonomous extraction cleaner that includes varioussystems and components schematically described for FIG. 1 , includingthe liquid delivery system 12 for storing and delivering a cleaningfluid to the surface to be cleaned and the recovery system 14 forextracting and storing the dispensed cleaning fluid, dirt and debrisfrom the surface to be cleaned. It is further contemplated thatintegrating a fluid supply system to the autonomous vacuum cleaner 810could result in the addition of a supply tank (not shown) to unit 812and a recovery container 820 that can be located, as a non-limitingexample, in the dirt bin 818.

The recovery container 820 can include a fluid level sensing assembly898, the details of which are not shown herein, connected to acontroller (not shown). Similarly to the fluid level sensing assembly 98from FIG. 4 , the fluid level sensing assembly 898 can include at leastone probe with at least one conductor wherein the fluid level sensingassembly 898 can detect a liquid or a foam level in the recoverycontainer 820. The fluid level sensing assembly 898 can complete one ormore methods 200, 200 a, 200 b, by taking measurements to determinecritical fluid level, liquid level, or foam level and acting on thedetermination.

FIG. 14 is an exploded perspective view of another recovery tankassembly 974, which can be utilized in the extraction cleaner 10 or acleaning apparatus as described above. The recovery tank assembly 974 issimilar to the recovery tank assembly 74; therefore, like parts will beidentified with like numerals increased by 900, with it being understoodthat the description of the like parts of the recovery tank assembly 74will apply to the recovery tank assembly 974, except where noted.

As with the previous assembly, the recovery tank assembly 974 includes,a pleated filter 984, filter cover plate 986, and mesh screen 988 at theair outlet 987 that can be located atop a lid 982 and the recoverycontainer 20 creates a seal therebetween for prevention of leaks.

A releasable latch 1100 is optionally provided on the lid 982 tofacilitate removal of the recovery tank assembly 974 for emptying orcleaning. The releasable latch 1100 can be configured to releasably lockthe recovery tank assembly 974 to the upright body, such that a usermust actuate the releasable latch 1100 before pulling the recovery tankassembly 974 off the frame 66. The hand grip 110 can be provided on therecovery container 920 and located below the latch 1100 to facilitatehandling of the recovery tank assembly 974.

Another difference is that a removable strainer 1150 is included andconfigured to strain large debris and hair out of the recovery container920 prior to emptying. The removable strainer 1150 is configured tocollect the large debris and hair while draining fluid (e.g. liquid) andsmaller debris back into the recovery container 920. One example of asuitable strainer is disclosed in U.S. patent application Ser. No.15/827,790, filed Nov. 30, 2017, which is incorporated herein byreference in its entirety. For purposes of this description, largedebris are any debris with a maximum dimension, such as a length ordiameter, of greater than or equal to 0.5 mm to 6 mm, and preferably 3mm, whereas small debris are any debris having a maximum dimension, suchas a length or diameter, of less than that of the larger debris. Anexample of a piece of large debris includes a strand of hair with alength greater than 3 mm. Examples of small debris include coffeegrounds and crumbs with diameters less than 3 mm.

The removable strainer 1150 can includes an elongated handle or grip1152 and a base 1154. The removable strainer 1150 can be removablymounted within the recovery container 920 such that the base 1154 is ata bottom end of the recovery container 920 and the grip 1152 extendstoward a top end of the tank container 258 (FIG. 15 ). The base 1154 caninclude a plurality of drain holes 1156 for draining fluid when theremovable strainer 1150 is removed from the recovery container 920, andoptionally a raised rim 1158 around its perimeter for containing debris.An opening 1160 can also be provided in the base 1154 for accommodatinga standpipe 923 (FIG. 15 ). The base 1154 can form a cup-shaped colanderthat retains large debris and hair.

The drain holes 1156 can be circular or non-circular openings orapertures in the base 1154. In one example, the size of the drain holes1156 can range in diameter from 0.5 mm to 6 mm, and optionally from 3 mmto 4 mm. Other examples of drain holes 1156 are possible, including theremovable strainer 1150 having a grid or mesh on the base 1154 definingthe drain holes 1156.

As better illustrated in FIG. 15 , a collection chamber 921 is formed bythe recovery container 920 for the fluid recovery system and includes ahollow standpipe 923 therein. The standpipe 923 can be oriented suchthat it is generally coincident with a longitudinal axis of the recoverycontainer 920. The standpipe 923 forms a flow path between a tank inlet925 formed at a lower end of the recovery container 920 and a tankoutlet 927 at the upper end of the standpipe 923 within the interior ofthe recovery container 920. When the recovery tank assembly 974 ismounted to the frame 66, the tank inlet 925 is aligned with thepivotable swivel joint assembly and conduit therein to establish fluidcommunication between the base 14 and the recovery tank assembly 974.The standpipe 923 can be integrally formed with the tank container 258.

The base 1154 can be configured to fit within the recovery container 920at a location spaced from a bottom wall 925 thereof. When the removablestrainer 1150 is inserted into the recovery container 920, fluid andsmall debris can pass through the drain holes 1156 to the area of thecollection chamber 921 below the base 1154, while large debris and hairis trapped above the base 1154. Optionally, a stop 927 can be providedon the standpipe 923 that limits the insertion of the removable strainer1150 into the recovery container 920 to maintain the base 1154 spacedabove the bottom wall 292.

As shown, the grip 1152 can extends upwardly and/or vertically along theinner surface of the recovery container 920 and can be oriented suchthat it is generally parallel to the longitudinal axis of the recoverycontainer 920, and optionally also to the standpipe 923. The strainer1150 shown herein is further inserted and removed from the recoverycontainer 920 along a direction that is parallel to, or coincident with,the longitudinal axis of the recovery container 920. The base 1154extends from a lower end of the grip 1152 to substantially cover thebottom wall 925 of the recovery container 920, such that any largedebris/hair is trapped by the base 1154 above the bottom wall 925. Thegrip 1152 can be offset and relatively slender to maximize spaceavailable in the recovery container 920 for collecting debris and fluid.

In typical recovery tanks, large debris and hair is not strained out andis disposed of together with the fluid waste (e.g. liquid waste), whichcan potentially result in clogged drains and pipes. Alternatively, largedebris and hair can be manually picked out of the recovery tank, whichis unsanitary and laborious. With the removable strainer 1150, a usercan simply remove the lid 982 and lift the removable strainer 1150 out.The removable strainer 1150 separates out large debris and hair whilefluid and smaller debris drains back into the recovery container 920.The long grip 1152 prevents a user from contact with any of thecollected debris or fluid. Thus, a user can easily and sanitarilydispose of any large debris and hair in the trash, prior to emptying thefluid waste down a sink, toilet, or other drain thereby avoiding theproblems with prior recovery tanks. The removable strainer 1150 can beparticularly helpful for use with a multi-surface vacuum cleaner becausethese types of vacuum cleaners ingest wet and dry debris, includinglarge dry debris, and deposit the debris mixture into a single recoverytank.

A shut-off valve 1163 (FIG. 16 ) can be provided for interruptingsuction when liquid or foam in the recovery container 920 reaches apredetermined level. The shut-off valve can be positioned in anysuitable manner and include any suitable type of valve. The fluid levelsensing assembly 998 can be configured to determine when such shut-offvalve should be activated. The fluid level sensing assembly 998 caninclude any suitable assembly for sensing one of at least liquid or foamat one or more levels within the recovery container 920 or otherportions of the extraction cleaner 10. In the illustrated example, atleast one side bracket assembly 992 a, 992 b is fixedly attached to thelid 982 in a position offset from the standpipe 923. Further still, atleast one front bracket assembly 92 c is attached to the lid 82 adjacentan air outlet 96.

FIG. 16 is a schematic view of the sensing system 996. The probes orsensors 1162, 1164 are coupled with a controller 1122. The controller1122 can also be operationally connected to other components of theapparatus 10, as described in further detail below. The first sensor1162 can emit a liquid sensing signal 1136 from the controller 1122 at agiven frequency 1138. The liquid sensing signal 1136 travels throughcontents of the recovery container 920 to form a liquid response signal1140 that is detected by the second sensor 1164 and communicated to thecontroller 1122. The second sensor 1164 can be located in the recoverycontainer 920 at a critical liquid level 1165. The term critical liquidlevel is used herein to define a level or location where, if liquid ispresent, at least one electrical component of the apparatus 10 is shutdown to prevent liquid ingress into the suction source 18. If the liquidresponse signal 1140 indicates that the liquid in the recovery container920 is at or above the critical level 1165, the controller 1122 can turnoff the at least one electrical component of the apparatus 10. Suchcomponents can include the suction source 18 itself, and moreparticularly the vacuum motor, and optionally also the pump 40 and/orthe brush motor for the agitator 26. As illustrated, the controller 1122can additionally or alternatively activate a shut-off valve 1163 inresponse to the liquid response signal 1140 to prevent liquid ingressinto the suction source 18. The shut-off valve 1163 can be provided forinterrupting suction when liquid in the recovery container 920 reachesthe critical level 1165.

Additionally or alternatively, the controller 1122 based on the liquidresponse signal 1140 can provide a visual or audible status indicationsuch as a light or sound via the user interface or SUI 1132. The visualor audible status indication can alert the user that the liquid is toohigh in the recovery tank or that a component of the apparatus 1210 hasbeen turned off. It is also contemplated that the controller 1122 candetect a presence or an absence of the recovery container 920 with theinclusion of a resistor with high resistance (not shown) coupled betweenthe first sensor 1162 and the second sensor 1164 and that such presenceor absence can be indicated on the user interface 1132.

Another aspect of the disclosure includes a cleaning apparatus orextraction cleaner 1210 with a conductivity sensing system 1296 is shownin FIG. 17 . The extraction cleaner 1210 is similar to the extractioncleaner 10 therefore, like parts will be identified with like numeralsincreased by 1200, with it being understood that the description of thelike parts of the extraction cleaner 10 will apply to the extractioncleaner 1210, except where noted. Further still, the extraction cleaner1200 includes a sensing system similar to the sensing system 996 it willbe understood that the description of the like parts will apply to thesensing system, except where noted. One difference is that the twosensors or probes instead of being suspended within the recoverycontainer 1220 are located within the exterior sidewalls of the recoverycontainer 1220.

As illustrated more clearly in FIG. 18 the recovery container 1220includes recesses 1221 formed into two opposing side walls of therecovery container 1220. A first sensor 1314 and a second sensor 1316each include a set of pins insert-molded, generally illustrated atconductive pad 1315 into the recesses 1221 of the recovery container.The set of pins can include a generally vertical configuration andterminal ends 1315 a of the set of pins can be received in correspondingelectrical connectors 1314 a and 1316 a (FIG. 19 ) spaced about aconduit 927 located in the base 1276. The electrical connectors 1314 aand 1316 a can be operably coupled to a controller (not shown) for theextraction cleaner 1210. The first sensor 1314 and second sensor 1316operate similarly to those within the sensing system 996 and coupledwith the controller including that they are configured to conductivelysense critical liquid levels and action can be taken based thereonincluding operation of at least one electrical component of theapparatus 1210 to shut down to prevent liquid ingress or alert a uservia the user interface.

FIG. 20 illustrates another exemplary cleaning apparatus or extractioncleaner 1410, which is similar to the extraction cleaner 10 therefore,like parts will be identified with like numerals increased by 1400, withit being understood that the description of the like parts of theextraction cleaner 10 will apply to the extraction cleaner 1410, exceptwhere noted. One difference is that the recovery tank assembly 1474 doesnot include sensors suspended within the recovery container; instead, asensor 1514 is attached to a wall 1515 of the frame 1466 of the uprighthandle assembly 1460 adjacent to where the recovery tank assembly 1474is received in the body assembly 1470. FIG. 21 is a cross-sectional viewthough the assembled recovery tank assembly of FIG. 20 where it can bebetter illustrated that the recovery tank 1420 abuts against the wall1515, which is only partially shown. A sensor assembly 1514 can belocated adjacent the wall 1515. While the wall is illustrated asincluding brackets for holding the sensor assembly 1514 in place it willbe understood that this is merely by way of non-limiting example andthat any suitable mechanism can be utilized to place the sensor assembly1514.

Unlike the sensing systems previously described the sensor assembly 1514can include a self-capacitive sensing system where the probes 1517 (FIG.22 ) are conductive pads mounted on the wall 1515 behind the recoverycontainer 1420. It will be understood that the recovery container 1420and sensor assembly 1514 can be abutting, adjacent, or spaced via air orthe wall 1515 in any suitable configuration. Wall thickness of therecovery tank 1420 is generally below 3 mm and made of plasticmaterials. The wall thickness of the wall 1515 can vary and a small airgap can be located between walls.

As illustrated more clearly in FIG. 22 the probes 1517 can be placedalong a height of the recovery container 1420 such that the sensorassembly 1514 is configured to sense or detect multiple liquid levelswithin the recovery container 1420 and can detect liquid levels based onorientation of the recovery tank 1420. The sensor assembly 1514 can beoperably coupled to the controller 1522 to provide outputs thereto.Having the sensor assembly 1514 removed or separate from the recoverycontainer 1420 can provide for additional robustness as compared toexamples where the sensors are located within or on the recovercontainer or lid.

Further still, an accelerometer 1519 can be included such that thesensing system 1496 can estimate the tank fill level or volume of liquidin the recovery container 1420 as the extraction cleaner 1410 isoperated as the accelerometer provides an orientation of the recoverycontainer 1420 and the capacitance sensing of the sensor assembly 1514provides a fluid level for the given orientation of the recoverycontainer 1420. The accelerometer 1519 has been illustrated as beinglocated with the controller 1522 schematically in FIG. 22 . It iscontemplated that the accelerometer 1519 can be located on a printedcircuit board (PCB) forming the controller 1522 or a portion of thecontroller 1522 and that such controller 1522 can be located in theupright handle assembly 1460 such that the recovery tank angle can bedetermined when the upright handle assembly 1460 is tilted during use.

During operation, the tilt of the recovery tank 1420 can be determinedby the controller 1522 via input from the accelerometer 1519 and thatinformation as well as the liquid level sensing from the self-capacitivesensor assembly 1514 can be utilized by the controller 1522 to determinea liquid level within the recovery tank 1420. In this manner, thecontroller 1522 can determine that at high liquid levels detected viathe sensor assembly 1514 and at a high tilt from vertical as determinedutilizing the accelerometer 1519, a critical liquid level has not beenreached. This can prevent triggering of a false critical liquid leveldetermination and abate unnecessary action by the extraction cleaner 10as a result. However, when it is determined based on information fromthe accelerometer 1519 and the sensor assembly 1514 that a criticalliquid level is present, the controller 1522 can take appropriateaction. For example, the controller 1522 can turn off at least oneelectrical component of the apparatus 1410 including the suction source1418 itself, and more particularly the vacuum motor, as well as the pump1440 and/or the brush motor for the agitator 1426. As illustrated, thecontroller 1522 can additionally or alternatively activate a shut-offvalve 1563 or can provide a visual or audible status indication such asa light or sound via the user interface 1532.

It will be understood that regardless of the particular sensing systemutilized that all aspects of the disclosure allow for level sensing inone or more tanks or containers of the apparatus including while theapparatus is in use or moving. The aspects of the disclosure remove orotherwise do not include mechanical float(s) in the fluid tank(s), inthis manner the sensing system can be considered to be floatless. Thisin turn provides for an improved cleanout experience of the recoverytank as no mechanical floats are present to retain or trap debris thatmust be cleaned to prevent float malfunction and undesirable odors.

In determining that a floatless or electronic sensing system would bebeneficial various other considerations and problems have beenconsidered including sloshing of liquid or foam within the containersbased on movement of the cleaning apparatus including translation andarticulation of the cleaning apparatus during operation. Aspects of thedisclosure including the exemplary sensing systems allow for the tanksto maintain full detection performance while operating. This includessensing levels in the tank regardless of debris therein, including forexample when wet hair bridges the sensor probes. Typical fluid levelelectronic sensing applications with a static tank, such as anindustrial chemical mixer or a tank that does not include debris such asa vehicle gas tanks would not include such considerations and thereforeare not applicable to cleaning apparatuses.

Any of the above sensing systems can be utilized to determine a level ofliquid within the container or tank. As described above, sensing systemsdisclosed herein include, by way of non-limiting examples, include ahigh frequency fluid and foam sensor including one example having threeprobes: one for transmitting and two receiving probes including one forfluid and one for foam sensing and another example includes two probeswith one transmitting probe and one receiving probe configured for fluidsensing. According to a method of operating, a non-DC signal or an ACdriving signal can be utilized. Such an AC driving signal can include,by way of non-limiting examples a high frequency square wave, a lowfrequency pulse width modulation (PWM) signal, etc. Further still, themethod of operating can include injecting a non-DC signal(s) into thecontainer or tank. Benefits of the method include that data can becollected faster than the rate of sloshing, which allows the sensingsystem to observe snapshots of the water level within the container. Acontroller of the sensing system can condition the signal such asthrough thresholding, averaging, etc. to figure out the actual fluidlevel. It will be understood that the frequency of the injected non-DCsignal can be selected based on factors like the geometry of the tank.Alternatively or additionally the frequency of the injected non-DCsignal can be selected based on properties of water or foam includingpermittivity or ability to hold electric energy, conductivity, etc.Taking these factors into consideration, the frequency can be selectedto increase detectability or better delineate between water and foam ifthe apparatus detects both.

Optionally, any of the sensing systems can include electronic componentsto capacitively couple and smooth the response signals such that therise time or the average amplitude of the voltage of the receivedsignals can be determined. Further, any of the respective controllerscan be configured to perform one or more signal processing algorithms onthe received response signals to determine one or more characteristicsof the received response signal. Signal processing algorithmsincorporated into the controller for assisting in the determination ofone or more characteristics of the received signals can include, but arenot limited to, blind source separation, principal component analysis,singular value decomposition, wavelet analysis, independent componentanalysis, cluster analysis, Bayesian classification, etc. It iscontemplated that any of the sensors of the sensing system can beconfigured to transmit, receive or transmit and receive one or moresensing signals. The sensing signals can include any waveform useful insensing liquid, including, but not limited to, square waves, sine waves,triangle waves, sawtooth waves, and combinations thereof. Furthermore,the sensing signals can include any frequency useful in sensing liquid,including, but not limited to, frequencies ranging from approximately 10kilohertz to 10 megahertz. In one non-limiting example, the liquidsensing signals can be multiplexed and transmitted simultaneously to oneor more sensors.

The slew rate of the operational amplifier, which is the time it takesto respond to a change in voltage, is critical for high frequencyoperation within the above described cleaning apparatuses. The slew ratehelps identify the maximum input frequency and amplitude applicable tothe amplifier such that the output is not significantly distorted. Ithas been determined that a slew rate of approximately 15 V/us can bebeneficial and that a performance drop-off was detected at a slew rateof 1 V/us and below.

One advantage that can be realized according to aspects of the presentdisclosure is that the recovery container that requires occasionalremoval for emptying, is easier to reattach to the extraction cleanerdue to the absence of additional liquid measuring components, such as afloat. Another advantage is that frequency measurements can be utilizedallowing for the accurate detection of liquid and foam. Frequencymeasurements enable the extraction cleaner to distinguish between liquidand foam and accurately detect the respective levels of each. Thefeatures, alone or in combination, create a superior indication systemfor extraction cleaners. Another benefit that can be achieved is thatlevels of fluid or foam can be sensed and a user can be alerted orportions of the apparatus shut off, including valving, so that overflowdoes not occur.

To the extent not already described, the features and structures of thevarious aspects of the present disclosure of the extraction cleaners,systems, and methods may be used in combination with each other asdesired. That one feature may not be illustrated in all of theembodiments is not meant to be construed that it cannot be, but is donefor brevity of description. Thus, the various features of theembodiments disclosed herein may be mixed and matched as desired to formnew embodiments, whether or not the new embodiments are expresslydescribed. Furthermore, while the extraction cleaners shown herein areupright or robot cleaners, features of the disclosure may alternativelybe applied to canister-type, stick-type, handheld, or portableextraction cleaners.

It is intended that the following claims define the scope of theinvention and that the method(s) and/or apparatus within the scope ofthese claims and their equivalents be covered thereby. This descriptionof the invention should be understood to include all novel andnon-obvious combinations of elements described herein, and claims may bepresented in this or a later application to any novel and non-obviouscombination of these elements. Any aspect of any embodiment can becombined any aspect of any of the other embodiments. Moreover, theforegoing embodiments are illustrative, and no single feature or elementis essential to all possible combinations that may be claimed in this ora later application. For example, various characteristics, aspects, andadvantages of the present invention may also be embodied in thefollowing technical solutions defined by the following clauses and mayinclude any combination of the following concepts:

A surface cleaning device, including:

-   -   a base adapted for contacting a surface of a surrounding        environment to be cleaned;    -   a suction source;    -   a suction nozzle assembly provided on the base and defining a        suction nozzle in fluid communication with the suction source;    -   a fluid delivery and recovery system, comprising:        -   a fluid supply tank adapted to hold a supply of fluid;        -   a fluid dispenser in fluid communication with the fluid            supply tank; and        -   a recovery tank in fluid communication with the suction            nozzle;    -   a fluid level sensing assembly, comprising:        -   at least one probe; and        -   a controller communicatively coupled to the at least one            probe and configured to electronically control the at least            one probe and configured to detect a level of fluid in at            least one of the fluid supply tank or the recovery tank to            define a presence of liquid.

The surface cleaning device of any of the disclosed aspects wherein thecontroller is further configured to determine an operational status ofthe fluid delivery system based on the detected fluid level.

The surface cleaning device of any of the disclosed aspects wherein thefluid level sensing assembly further comprises an accelerometercommunicatively coupled to the controller and outputting a signal to thecontroller.

The surface cleaning device of any of the disclosed aspects wherein thecontroller is further configured to estimate a volume of liquid withinthe recovery tank based on the signal from the accelerometer.

The surface cleaning device of any of the disclosed aspects wherein thecontroller is further configured to detect a presence of foam in atleast one of the fluid supply tank or the recovery tank.

The surface cleaning device of any of the disclosed aspects whereindetecting the presence of liquid or detecting the presence of foam, thecontroller is further configured to at least one of de-energize acomponent or provide an alert.

The surface cleaning device of any of the disclosed aspects wherein theat least one probe is located on a bracket assembly that is containedwithin the recovery tank.

The surface cleaning device of any of the disclosed aspects wherein thebracket assembly is operably coupled to a lid of the recovery tank.

The surface cleaning device of any of the disclosed aspects wherein theat least one probe is disposed within a side wall of the recovery tank.

The surface cleaning device of any of the disclosed aspects wherein thesurface cleaning device is one of an upright vacuum cleaner, amulti-surface floor cleaner, a robotic vacuum, a canister vacuum, aportable deep cleaner, an upright deep cleaner, or a commercialextractor.

The surface cleaning device of any of the disclosed aspects wherein thecontroller is further configured to detect a presence of the recoverytank based on a signal from the at least one probe.

The surface cleaning device of any of the disclosed aspects wherein theat least one probe comprises a first probe configured to emit a liquidsensing signal at a first frequency and a second probe configured todetect a liquid response signal.

The surface cleaning device of any of the disclosed aspects wherein thefirst frequency is greater than 10 kilohertz.

The surface cleaning device of any of the disclosed aspects wherein thefirst frequency is greater than 100 kilohertz.

The surface cleaning device of any of the disclosed aspects wherein theliquid sensing signal is one of a square wave, a sine wave, a trianglewave, or a sawtooth wave.

The surface cleaning device of any of the disclosed aspects wherein thefirst probe is further configured to emit a foam sensing signal at asecond frequency.

The surface cleaning device of any of the disclosed aspects wherein thesecond frequency is greater than 40 kilohertz.

The surface cleaning device of any of the disclosed aspects wherein thesecond frequency is greater than 10 kilohertz.

The surface cleaning device of any of the disclosed aspects wherein theat least one probe further comprises a third probe configured to detecta foam response signal.

The surface cleaning device of any of the disclosed aspects wherein thethird probe is positioned above the second probe.

The surface cleaning device of any of the disclosed aspects wherein thecontroller is operationally connected to at least one of the suctionsource, a pump, an agitator, or a user interface.

The surface cleaning device of any of the disclosed aspects wherein thecontroller is further configured to deenergize the at least one of thesuction source, the pump, the agitator, or the user interface based onthe liquid response signal detected at the second probe.

The surface cleaning device of any of the disclosed aspects wherein thecontroller is further configured to deenergize at least one component ofthe suction source upon detection of foam based on a signal detected atthe third probe.

The surface cleaning device of any of the disclosed aspects wherein thefluid level sensing assembly further comprises at least one componentelectrically coupled between the at least one probe and the controllerand configured to output an average voltage representative of the liquidresponse signal.

The surface cleaning device of any of the disclosed aspects wherein thefluid level sensing assembly further comprises at least one componentelectrically coupled between the at least one probe and the controllerand configured to output an average voltage representative of the foamresponse signal.

The surface cleaning device of any of the disclosed aspects wherein thefluid level sensing assembly further comprises at least one componentelectrically coupled between the at least one probe and the controllerand configured to output a signal representative of the average risetime of the foam response signal.

The surface cleaning device of any of the disclosed aspects wherein thefluid level sensing assembly further comprises at least one componentelectrically coupled between the at least one probe and the controllerand configured to output an average voltage representative of the liquidresponse signal.

The surface cleaning device of any of the disclosed aspects wherein thefluid level sensing assembly further comprises at least one componentelectrically coupled between the at least one probe and the controllerand configured to output a signal representative of the average risetime of the liquid response signal.

The surface cleaning device of any of the disclosed aspects wherein thefluid level sensing assembly further comprises at least one componentconfigured to capacitively couple the at least one probe to thecontroller.

The surface cleaning device of any of the disclosed aspects wherein thecontroller further comprises an operational amplifier with a slew rategreater than 1 volt per microsecond.

The surface cleaning device of any of the disclosed aspects wherein thecontroller is further configured to respond to a signal that changes ata rate greater than 1 volt per microsecond.

The surface cleaning device of any of the disclosed aspects wherein theat least one probe is configured to emit a liquid sensing signal at afirst frequency and to emit a foam sensing signal at a second frequency.

The surface cleaning device of any of the disclosed aspects wherein theat least one probe is configured to concurrently emit the liquid sensingsignal and the foam sensing signal.

The surface cleaning device of any of the disclosed aspects wherein theat least one probe is configured to consecutively emit the liquidsensing signal and the foam sensing signal.

The surface cleaning device of any of the disclosed aspects wherein theliquid sensing signal is one a square wave.

A sensing system for a cleaning apparatus, the sensing system comprisinga sensor assembly including at least one electrical sensor configured tooutput a first signal indicative of a liquid level within a tank of thecleaning apparatus and a controller communicatively coupled to the atleast one sensor and configured to electronically control the at leastone sensor and configured to detect a level of fluid in the tank todefine a presence of liquid.

The sensing assembly of any of the disclosed aspects further comprisingan accelerometer communicatively coupled to the controller andoutputting a second signal indicative of a tilt angle of the tank.

The sensing assembly of any of the disclosed aspects wherein thecontroller is further configured to estimate a volume of liquid withinthe recovery tank based on the first signal from the at least one sensorand the second signal from the accelerometer.

The sensing assembly of any of the disclosed aspects wherein the atleast one electrical sensor includes a self-capacitive sensor having aplurality of probes and wherein the first signal indicates one of aplurality of liquid levels within the tank.

The sensing assembly of any of the disclosed aspects wherein theaccelerometer is located on a printed circuit board of the controller.

A method for operating a cleaning apparatus, the method comprising:operating a recovery system of the cleaning apparatus wherein a suctionnozzle in fluid communication with a suction source is fluidly coupledto a recovery tank, outputting a signal from at least one electricalsensor related to the recovery tank; and determining, via a controller,from the signal a level of fluid in the tank.

Any of the disclosed aspects further comprising outputting a secondsignal from an accelerometer communicatively coupled to the controller.

Any of the disclosed aspects wherein the controller is furtherconfigured to estimate a volume of liquid within the recovery tank basedon the second signal from the accelerometer.

Any of the disclosed aspects further comprising de-energizing, via thecontroller, a component of the cleaning apparatus or provide an alertvia a user interface.

Any of the disclosed aspects wherein the at least one electrical sensoris located on a bracket assembly that is contained within the recoverytank.

Any of the disclosed aspects wherein the bracket assembly is operablycoupled to a lid of the recovery tank.

Any of the disclosed aspects wherein the at least one electrical sensoris disposed within a side wall of the recovery tank.

Any of the disclosed aspects wherein the surface cleaning device is oneof an upright vacuum cleaner, a multi-surface floor cleaner, a roboticvacuum, a canister vacuum, a portable deep cleaner, an upright deepcleaner, or a commercial extractor.

Any of the disclosed aspects further comprising detecting a presence ofthe recovery tank based on the signal.

While the aspects of the present disclosure have been specificallydescribed in connection with certain specific embodiments thereof, it isto be understood that this is by way of illustration and not oflimitation. Reasonable variation and modification are possible with thescope of the foregoing disclosure and drawings without departing fromthe spirit of the invention which, is defined in the appended claims.Hence, specific dimensions and other physical characteristics relatingto the embodiments disclosed herein are not to be considered aslimiting, unless the claims expressly state otherwise.

What is claimed is:
 1. A surface cleaning device, comprising: a suctionsource; a base adapted for contacting a surface of a surroundingenvironment to be cleaned and comprising a suction nozzle in fluidcommunication with the suction source; a fluid supply tank adapted tohold a supply of fluid; a fluid dispenser in fluid communication withthe fluid supply tank; a recovery container in fluid communication withthe suction nozzle; a standpipe in the recovery container, the standpipeforming a flow path between an inlet to the recovery container and anoutlet at an upper end of the standpipe; and a sensing assembly,comprising: at least one probe suspended in the recovery container in aposition offset from the standpipe, the at least one probe comprising aconductor; and a controller communicatively coupled to the at least oneprobe, wherein the controller is configured to detect a level of fluidin the recovery container to define a presence of liquid.
 2. The surfacecleaning device of claim 1 wherein the sensing assembly comprises anaccelerometer communicatively coupled to the controller and outputting asignal to the controller, wherein the controller is configured toestimate a volume of liquid within the recovery container based on thesignal from the accelerometer.
 3. The surface cleaning device of claim 1wherein the controller is configured to detect at least one of: apresence of foam in the recovery container; and a presence of therecovery container.
 4. The surface cleaning device of claim 1 whereinthe at least one probe comprises a first probe, and the sensing assemblycomprises a second probe.
 5. The surface cleaning device of claim 4wherein the sensing assembly comprises at least one component configuredto capacitively couple the second probe to the controller.
 6. Thesurface cleaning device of claim 4 wherein the sensing assemblycomprises a third probe, wherein the third probe is positioned above thesecond probe.
 7. The surface cleaning device of claim 4 wherein therecovery container comprises: a lid; a first bracket assembly coupledwith the lid supporting the first probe; and a second bracket assemblycoupled with the lid supporting the second probe.
 8. The surfacecleaning device of claim 4, wherein the first and second probes areoffset from the standpipe on opposing sides of the standpipe.
 9. Thesurface cleaning device of claim 1 wherein the recovery containercomprises: a lid; an air outlet in the lid; and a filter removablymounted in the lid to filter air exiting the recovery container via theair outlet.
 10. The surface cleaning device of claim 9 wherein the atleast one probe is coupled with an underside of the lid and the filteris removable from an upper side of the lid.
 11. The surface cleaningdevice of claim 1 wherein: the controller is operationally connected toat least one of the suction source, a pump, an agitator, or a userinterface; and the controller is configured to deenergize the at leastone of the suction source, the pump, the agitator, or the user interfacebased on input from the sensing assembly.
 12. The surface cleaningdevice of claim 1, comprising a body assembly, wherein the recoverycontainer is removably mounted to the body assembly.
 13. The surfacecleaning device of claim 12, wherein the controller is configured todetect a presence or an absence of the recovery container via input fromthe sensing assembly.
 14. The surface cleaning device of claim 13,comprising a user interface in communication with the controller,wherein the controller is configured indicate via the user interface thepresence or the absence of the recovery container.
 15. The surfacecleaning device of claim 1 wherein the surface cleaning device is one ofan upright vacuum cleaner, a multi-surface floor cleaner, a roboticvacuum, a canister vacuum, a portable deep cleaner, an upright deepcleaner, or a commercial extractor.
 16. A surface cleaning device,comprising: a suction source; a base adapted for contacting a surface ofa surrounding environment to be cleaned and comprising a suction nozzlein fluid communication with the suction source; a fluid supply tankadapted to hold a supply of fluid; a fluid dispenser in fluidcommunication with the fluid supply tank; a recovery containercomprising a tank inlet in fluid communication with the suction nozzle;a lid sized for receipt on the recovery container; a standpipe in therecovery container, the standpipe forming a flow path between the tankinlet and an outlet at an upper end of the standpipe; and a sensingassembly, comprising: a controller configured to detect a level of fluidin the recovery container to define a presence of liquid and interruptsuction when liquid in the recovery container reaches a predeterminedlevel; a first probe coupled with the controller and suspended in therecovery container in a position offset from the standpipe, the firstprobe comprising a first conductor; and a second probe coupled with thecontroller and suspended in the recovery container in a position offsetfrom the standpipe, the second probe comprising a second conductor. 17.The surface cleaning device of claim 16 comprising: a first bracketassembly coupled with the lid and supporting the first probe; and asecond bracket assembly coupled with the lid and supporting the secondprobe.
 18. The surface cleaning device of claim 16 wherein thecontroller is configured to interrupt suction by deenergizing thesuction source when liquid in the recovery container reaches apredetermined level.
 19. The surface cleaning device of claim 16 whereinthe sensing assembly comprises at least one component configured tocapacitively couple the second probe to the controller.
 20. The surfacecleaning device of claim 16 comprising: an air outlet in the lid; and afilter removably mounted in the lid to filter air exiting the recoverycontainer via the air outlet; wherein the first and second probes aresuspended in the recovery container on an underside of the lid and thefilter is removable from an upper side of the lid.